Marine Polysaccharides Research Articles

A comparative investigation of anionic polysaccharides (sulfated fucan, ι-carrageenan, κ-carrageenan, and alginate) on the fabrication, stability, rheology, and digestion of multilayer emulsion

In this study, four important marine polysaccharides (sulfated fucan, ι-carrageenan, κ - carrageenan, and alginate) were selected and tailored to a similar molecular weight using heterologously overexpressed enzymes. These “standardized” polysaccharides were firstly used to elucidate the effect of anionic polysaccharides on the formation, stability, rheology, and digestion of the multilayer emulsions. Results showed that the four polysaccharides were all capable of adsorbing to the surfaces of lipid droplets at the pH values of 5, 4, and 3. ι-Carrageenan could adsorb to the surface of the droplet at a higher pH (pH 6) than the other three polysaccharides (pH 5). Stable multilayer emulsions were formed at a higher polysaccharide concentration (0.05 wt%) for κ-carrageenan compared with sulfated fucan, ι-carrageenan, and alginate (0.04 wt%). The emulsion containing alginate was susceptible to flocculation at low pH 3 and polysaccharide concentration >0.1 wt%. Multilayer emulsions fabricated by ι-carrageenan were stable under all the examined NaCl concentrations (0–400 mM). Multilayer emulsion fabricated by sulfated fucan showed less aggregation in the stomach stage, which is a good choice to encapsulate acid-intolerant substances. Multilayer emulsions fabricated by κ-carrageenan and alginate showed higher apparent viscosity, and the rheological curves of multilayer emulsions fabricated FUC or ICA were very similar. Moreover, multilayer emulsions fabricated by κ-carrageenan showed the fastest digestion rate and the highest digestion extent. These findings would facilitate the targeted design of multilayer emulsions by selecting suitable polysaccharides. • Four polysaccharides were tailed to similar molar mass by a repertoire of enzymes. • Multilayer emulsion with targeted functions was fabricated using polysaccharides. • ι-Carrageenan can fabricate multilayer emulsion with high salt stability demand. • κ-Carrageenan can form multilayer emulsion with the demand of rapid digestion. • Emulsion contained sulfated fucan had less aggregation in the stomach stage.

Algal and Cyanobacterial Polysaccharides as Promising Antiviral Agents against Human Viruses

Recently the morbidity, mortality and economic losses due to rapid transmission of Coronavirus (COVID-19) worldwide has incentivatedan urgent call for the scientists to discover efficient antiviral drugs for human health. Marine polysaccharides have long been recognized for their biological activities with huge application potentials in biomedical field. Their antiviral activities have been well documented against various types of infectious viruses and new studies proving their antiviral potential are frequently coming out.

Electrospinning of marine polysaccharides: Processing and chemical aspects, challenges, and future prospects

Abstract The association between electrospinning and polysaccharides corresponds to an important area under exploration, to meet the demands of biotechnological industries claiming for polymers with novel functional properties. Among the group of polysaccharides that attract attention for the manufacture of spun fibers; those from the marine origin that exhibit a remarkable potential, due to the possibilities to act as sulfated glycosaminoglycan mimics; as well as, exhibit an easily modifiable chemical structure that allow the production of derivatives suitable for biotechnological applications. Although electrospinning is a seemingly simple method, its applicability is not an easy task. The problem linked to the spinning of pure biomacromolecules has been generally evaluated embracing polymers from different origins. In this review, the parameters affecting the electrospinning of different marine polysaccharides in their pure form will be considered. The chemical features of these polysaccharides as well as the rheological aspects of their solutions will be in depth analyzed, emphasizing the difficulties associated with the use of water as the working solvent. Strategies used to produce spun fibers from other polymers will be also analyzed in this review, proposing them as an alternative to be studied when the production of spun fibers of marine polysaccharides is envisaged.

Chain conformation, mucoadhesive properties of fucoidan in the gastrointestinal tract and its effects on the gut microbiota

Fucoidans are valuable marine polysaccharides with various bioactivities and physicochemical properties. However, its digestive properties, mucoadhesive properties, and bioactivity in the gastrointestinal tract are still unclear. In this study, simulated digestion, fecal fermentation in vitro, and rheology models were utilized to investigate the chain conformation, influence on gut microbiota, and mucin adhesive properties of fucoidan from the sea cucumber Thelenota ananas (Ta-FUC). The results showed that Ta-FUC was nondigestible with a temporary decrease in molecular weight in gastric conditions, accompanied by the chain conformation becoming more flexible. Moreover, Ta-FUC exhibited strong mucin adhesive function in the simulated intestinal environment, with supramolecular disulfide, hydrogen, and hydrophobic interactions in order of intensity. During fermentation, Ta-FUC was degraded by the intestinal flora to produce various short-chain fatty acids and promoted the relative abundance of Bacteroidota and Firmicutes, reducing the proportion of Proteobacteria. Therefore, these results indicate that Ta-FUC could be a potential prebiotic and ingredient for developing targeted delivery systems in the functional food and pharmaceutical industries.

Green approaches for extraction, chemical modification and processing of marine polysaccharides for biomedical applications.

Over the past few decades, natural-origin polysaccharides have received increasing attention across different fields of application, including biomedicine and biotechnology, because of their specific physicochemical and biological properties that have afforded the fabrication of a plethora of multifunctional devices for healthcare applications. More recently, marine raw materials from fisheries and aquaculture have emerged as a highly sustainable approach to convert marine biomass into added-value polysaccharides for human benefit. Nowadays, significant efforts have been made to combine such circular bio-based approach with cost-effective and environmentally-friendly technologies that enable the isolation of marine-origin polysaccharides up to the final construction of a biomedical device, thus developing an entirely sustainable pipeline. In this regard, the present review intends to provide an up-to-date outlook on the current green extraction methodologies of marine-origin polysaccharides and their molecular engineering toolbox for designing a multitude of biomaterial platforms for healthcare. Furthermore, we discuss how to foster circular bio-based approaches to pursue the further development of added-value biomedical devices, while preserving the marine ecosystem.

Adhesive and Antibacterial Films Based on Marine-Derived Fucoidan and Chitosan

Marine-derived polymers are environmentally friendly and sustainable biomaterials that have structural similarities with the main components of the extracellular matrix. Moreover, some marine polymers have specific bioactivity that can be transferred to the systems made of these biomolecules. Herein, we developed antibacterial adhesive films combining two marine polysaccharides, namely, fucoidan and chitosan. Fucoidan was functionalized with catechol groups (FCat) to improve its adhesive properties. This modification enhanced also the fucoidan antibacterial properties: while fucoidan is active against Gram-positive bacteria, FCat showed bactericidal activity against Gram-positive and Gram-negative bacteria. To improve the processability and mechanical properties, FCat was blended with chitosan and solvent-casted to obtain films. These films exhibited an adhesion strength similar to the one of clinically used natural adhesives and no cytotoxicity: fibroblastic cells attached and remained viable on the films. Altogether our results demonstrated that the developed antibacterial and adhesive films are a feasible alternative of cytotoxic synthetic adhesives used for soft tissue healing applications.

Sulfated polysaccharides derived from marine microalgae, Synechococcus sp. VDW, inhibit the human colon cancer cell line Caco-2 by promoting cell apoptosis via the JNK and p38 MAPK signaling pathway

This study offers an examination of the physicochemical qualities of marine microalgae-derived sulfated polysaccharides (MMPS) from Synechococcus sp. VDW along with an investigation of their antioxidant and antitumor activities. On average, MMPS offered a molecular weight of 190.94 kDa with sulfate content of 16.83 %. There were shown to be four different monosaccharides contained within MMPS. The anticancer characteristics of human colon cancer cell lines (Caco-2) were also investigated. Flow cytometry revealed that MMPS triggered apoptosis at doses of 1 mg mL−1. Meanwhile, analysis of gene and apoptosis protein expression demonstrated that MMPS increased apoptosis in Caco-2 cells via the p38 MAPK and JNK signaling pathways. These findings contribute to our current understanding of how MMPS helps promote tumor suppression. In conclusion, the possibility that MMPS may possess anticancer qualities in the treatment of human colon cancer makes it an appealing candidate for anticancer polysaccharide combinations with chemotherapeutic agents and functional foods.

NMR Analyses of the Enzymatic Degradation End-Products of Diabolican: The Secreted EPS of Vibrio diabolicus CNCM I-1629.

Diabolican, or HE800, is an exopolysaccharide secreted by the non-pathogenic Gram-negative marine bacterium Vibrio diabolicus (CNCM I-1629). This polysaccharide was enzymatically degraded by the Bacteroides cellulosilyticus WH2 hyaluronan lyase. The end products were purified by size-exclusion chromatography and their structures were analyzed in depth by nuclear magnetic resonance (NMR). The oligosaccharide structures confirmed the possible site of cleavage of the enzyme showing plasticity in the substrate recognitions. The production of glycosaminoglycan-mimetic oligosaccharides of defined molecular weight and structure opens new perspectives in the valorization of the marine polysaccharide diabolican.

A Comprehensive Review of the Cardioprotective Effect of Marine Algae Polysaccharide on the Gut Microbiota.

Cardiovascular disease (CVD) is the number one cause of death worldwide. Recent evidence has demonstrated an association between the gut microbiota and CVD, including heart failure, cerebrovascular illness, hypertension, and stroke. Marine algal polysaccharides (MAPs) are valuable natural sources of diverse bioactive compounds. MAPs have many pharmaceutical activities, including antioxidant, anti-inflammatory, immunomodulatory, and antidiabetic effects. Most MAPs are not utilized in the upper gastrointestinal tract; however, they are fermented by intestinal flora. The relationship between MAPs and the intestinal microbiota has drawn attention in CVD research. Hence, this review highlights the main action by which MAPs are known to affect CVD by maintaining homeostasis in the gut microbiome and producing gut microbiota-generated functional metabolites and short chain fatty acids. In addition, the effects of trimethylamine N-oxide on the gut microbiota composition, bile acid signaling properties, and CVD prevention are also discussed. This review supports the idea that focusing on the interactions between the host and gut microbiota may be promising for the prevention or treatment of CVD. MAPs are a potential sustainable source for the production of functional foods or nutraceutical products for preventing or treating CVD.

Rhamnan sulfate reduces atherosclerotic plaque formation and vascular inflammation

ObjectiveWhile lipid-lowering drugs have become a mainstay of clinical therapy these treatments only slow the progression of the disease and can have side effects. Thus, new treatment options are needed to supplement the effects of lipid lowering therapy for treating atherosclerosis. We examined the use of an inexpensive and widely available marine polysaccharide rhamnan sulfate as an oral therapeutic for limiting vascular inflammation and atherosclerosis. Methods and resultsWe found rhamnan sulfate enhanced the barrier function of endothelial cells, preventing the deposition of LDL and maintaining barrier function even in the presence of glycocalyx-degrading enzymes. Rhamnan sulfate was also found to bind directly to FGF-2, PDGF-BB and NF-κB subunits with high affinity. In addition, rhamnan sulfate was a potent inhibitor of NF-κB pathway activation in endothelial cells by TNF-α. We treated ApoE−/− mice with a high fat diet for 4 weeks and then an addition 9 weeks of high fat diet with or without rhamnan sulfate. Rhamnan sulfate reduced vascular inflammation and atherosclerosis in both sexes of ApoE−/− mice but had a stronger therapeutic effect in female mice. Oral consumption of rhamnan sulfate induced a significant decrease in cholesterol plasma levels in female mice but not in male mice. In addition, there was a marked reduction in inflammation for female mice in the liver and aortic root in comparison to male mice. ConclusionsRhamnan sulfate has beneficial effects in reducing inflammation, binding growth factors and NF-κB, enhancing endothelial barrier function and reducing atherosclerotic plaque formation in ApoE−/− mice.

Valorization of Fish Waste: Isolation and Characterization of Acid- and Pepsin-Soluble Collagen from the Scales of Mediterranean Fish and Fabrication of Collagen-Based Nanofibrous Scaffolds.

In search of alternative and sustainable sources of collagenous materials for biomedical applications, the scales of five Mediterranean fish species-fished in high tonnage in the Mediterranean region since they represent popular choices for the local diet-as well as those of the Atlantic salmon for comparison purposes, were comparatively studied for their acid- and pepsin-soluble collagen content. Fish scales that currently represent a discarded biomass of no value could be efficiently exploited for the production of a high added-value biomaterial. The isolated collagenous materials, which showed the typical electrophoretic patterns of type I collagen, were morphologically and physicochemically characterized. Using scanning electron microscopy the fibrous morphology of the isolated collagens was confirmed, while the hydroxyproline content, in conjunction with infrared spectroscopy and X-ray diffraction studies verified the characteristic for collagen amino acid profile and its secondary structure. The acid- and pepsin-soluble collagens isolated from the fish scales were blended with the bioactive sulfated marine polysaccharide ulvan and polyethylene oxide and electrospun to afford nanofibrous scaffolds that could find applications in the biomedical sector.

Synergistic antibacterial activity of chitosan modified by double antibacterial agents as coating material for fruits preservation

Chitosan (CS) is a natural marine polysaccharide with good biocompatibility and biodegradability. But its poor water solubility and antibacterial activity limit its application in fruits preservation. In this study, based on the advantage of quaternary phosphonium salt (QP) and salicylic acid (SA) with good antibacterial activities and different antibacterial mechanisms, a novel antibacterial coating material was synthesized by grafting QP and SA onto CS. With the grafting of SA and QP onto CS, not only the crystallinity of CS molecules decreased and the water solubility improved, but also the antibacterial activity of CS-QP-SA against Escherichia coli and Staphylococcus aureus, and Colletotrichum gloeosporioides (anthracnose) improved by the synergistic effect of QP and SA. After 20 days storage, the mango fruits treated by CS-QP-SA had a weight loss rate of 12.86 %, the fruit decay incidence was 52.00 ± 1.70 %. Hence, the CS-QP-SA films effectively extending the storage time of mango fruits to a certain extent. The results of this study indicated that CS-QP-SA might be a promising preservative for fruits and vegetables.

Double-interpenetrating nanostructured networks of marine polysaccharides possessing properties comparable to synthetic polymers

Sustainable circular economy requires materials that possess a property profile comparable to synthetic polymers and, additionally, processing and sourcing of raw materials that have a small environmental footprint. Here, we present a paradigm for processing marine biopolymers into materials that possess both elastic and plastic behavior within a single system involving a double-interpenetrating polymer network comprising the elastic phase of dynamic physical cross-links and stress-dissipating ionically cross-linked domains. As a proof of principle, films possessing more than twofold higher elastic modulus, ultimate tensile strength, and yield stress than those of polylactic acid were realized by blending two water-soluble marine polysaccharides, namely alginic acid (Alg) with physically cross-linkable carboxylated agarose (CA) followed by ionic cross-linking with a divalent cation. Dried CAAlg films showed homogeneous nano-micro-scale domains, with yield stress and size of the domains scaling inversely with calcium concentration. Through surface activation/cross-linking using calcium, CAAlg films could be further processed using wet bonding to yield laminated structures with interfacial failure loads (13.2 ± 0.81 N) similar to the ultimate loads of unlaminated films (10.09 ± 1.47 N). Toward the engineering of wood-marine biopolymer composites, an array of lines of CAAlg were printed on wood veneers (panels), dried, and then bonded following activation with calcium to yield fully bonded wood two-ply laminate. The system presented herein provides a blueprint for the adoption of marine algae-derived polysaccharides in the development of sustainable high-performance materials.

Metabolic engineering enables Bacillus licheniformis to grow on the marine polysaccharide ulvan

BackgroundMarine algae are responsible for half of the global primary production, converting carbon dioxide into organic compounds like carbohydrates. Particularly in eutrophic waters, they can grow into massive algal blooms. This polysaccharide rich biomass represents a cheap and abundant renewable carbon source. In nature, the diverse group of polysaccharides is decomposed by highly specialized microbial catabolic systems. We elucidated the complete degradation pathway of the green algae-specific polysaccharide ulvan in previous studies using a toolbox of enzymes discovered in the marine flavobacterium Formosa agariphila and recombinantly expressed in Escherichia coli.ResultsIn this study we show that ulvan from algal biomass can be used as feedstock for a biotechnological production strain using recombinantly expressed carbohydrate-active enzymes. We demonstrate that Bacillus licheniformis is able to grow on ulvan-derived xylose-containing oligosaccharides. Comparative growth experiments with different ulvan hydrolysates and physiological proteogenomic analyses indicated that analogues of the F. agariphila ulvan lyase and an unsaturated β-glucuronylhydrolase are missing in B. licheniformis. We reveal that the heterologous expression of these two marine enzymes in B. licheniformis enables an efficient conversion of the algal polysaccharide ulvan as carbon and energy source.ConclusionOur data demonstrate the physiological capability of the industrially relevant bacterium B. licheniformis to grow on ulvan. We present a metabolic engineering strategy to enable ulvan-based biorefinery processes using this bacterial cell factory. With this study, we provide a stepping stone for the development of future bioprocesses with Bacillus using the abundant marine renewable carbon source ulvan.

Multifunctional nanoparticles based on marine polysaccharides for apremilast delivery to inflammatory macrophages: Preparation, targeting ability, and uptake mechanism

Hydrophobic drug encapsulation inside targeted nanoparticles can enhance accumulation in inflamed sites, limit toxicity to healthy tissue, and improve pharmacokinetics compared to free drug dosing. This study reports a functionalized marine polysaccharide nanoparticle with a controlled release, targeting abilities, and in-situ imaging properties. Carbon dots functionalized Enteromorpha polysaccharide/Mannose/Methionine functionalized Chitosan (CDs.EP/Man/Meth.Cs) NPs could deliver apremilast to inflammatory macrophages and Caco-2 intestinal cells as an in vitro model for application in oral drug delivery to cure IBD. The nanoparticles were simply a polyelectrolyte complex between cationic functionalized chitosan and anionic polysaccharide of Enteromorpha prolifera. Functionalized polysaccharides and the prepared NPs were well characterized. The functionalized nanoparticles could overcome the limitation of poor drug bioavailability and showed a high loading capacity of (45 %) with a controlled release of about (74.5 %). Confocal laser scanning imaging showed higher cellular uptake of the modified nanoparticles than that of the unmodified nanoparticles in LPS-activated RAW 264.7 macrophages and Caco-2 cells. The effect of functionalization on the cellular uptake targetability was assessed using spectrofluorometric measurements after mannose competition. Anti-inflammatory activity of apremilast-loaded NPs is more elevated than the free drug. These results suggest the feasibility of using functionalized EP/Cs nanoparticles in IBD oral drug delivery.

Intelligent films of marine polysaccharides and purple cauliflower extract for food packaging and spoilage monitoring

In this study, metalloanthocyanin-inspired, biodegradable packaging films were developed by incorporating purple cauliflower extracted (PCE) anthocyanins into alginate (AL)/carboxymethyl chitosan (CCS) hybrid polymer matrices based on complexation of metal ions with these marine polysaccharides and anthocyanins. PCE anthocyanins-incorporated AL/CCS films were further modified with fucoidan (FD) because this sulfated polysaccharide can form strong interactions with anthocyanins. Metals-involved complexation (Ca2+ and Zn2+-crosslinked films) improved the mechanical strength and water vapor permeability but reduced the swelling degree of the films. Zn2+-cross-linked films exhibited significantly higher antibacterial activity than did pristine (non-crosslinked) and Ca2+-cross-linked films. The metal ion/polysaccharide-involved complexation with anthocyanin reduced the release rate of anthocyanins, increased the storage stability and antioxidant capability, and improved the sensitivity of the colorimetric response of the indicator films for monitoring the freshness of shrimp. The anthocyanin-metal-polysaccharide complex film showed great potential as active and intelligent packaging of food products.

Lamellar agarose/graphene oxide gel polymer electrolyte network for all-solid-state supercapacitor

The application of gel polymer electrolyte (GPE) in solid state supercapacitor (SSC) has attracted much attention due to its excellent mechanical properties and chemical stability. However, traditional polymer substrates have high crystallinity, resulting in sluggish lithium migration and low ionic conductivity. In this work, density functional theory calculations (DFT) firstly reveal that agarose molecules (a natural marine polysaccharide) can be assembled to highly-ordered lamellar network structure by hydrogen bonds forming (d’ = 0.454 nm) as GPE matrix combining with graphene oxide (GO) addictive. Specifically, radial distribution functions (RDFs) show that intensities of peaks (gLi-O(r)) at 0.189 nm are 45.2 and 54.8 for agarose and agarose/GO, respectively. This finding indicates an optimized agarose molecular configuration and a rapid lithium migration in agarose/GO GPE (Ag/GO-GPE) system. When Ag/GO-GPE was prepared, SSC assembled with Ag/GO2-GPE and activated carbon electrode has high ionic conductivity (73.8 mS cm−1) and a specific capacitance as high as 791.67 mF cm−2 at a current density of 5 mA cm−2. Moreover, the electrochemical performance of SSC based Ag/GO2-GPE is stable at a bending condition of 180°, resulted from the hydrogen bonds between agarose matrix and GO. In addition, Ag/GO2-GPE has an excellent mechanical strength (0.115 MPa) and flame retardant performance (heat release rates (HRR) of 11.08 kw/m2 and total heat release (THR) of 0.79 MJ m2). This research opens up a novel avenue to develop safe and efficient flexible wearable SSCs.

Regulatory effects of marine polysaccharides on gut microbiota dysbiosis: A review.

The gut microbiota dysbiosis is a state which the physiological combinations of flora are transformed into pathological combinations caused by factors such as diets, pollution, and drugs. Increasing evidence shows that dysbiosis is closely related to many diseases. With the continuous development and utilization of marine resources, marine polysaccharides have been found to regulate dysbiosis in many studies. In this review, we introduce the types of dysbiosis and the degree of it caused by different factors. We highlight the regulating effects of marine polysaccharides on dysbiosis as a potential prebiotic. The mechanisms of marine polysaccharides to regulate dysbiosis including protection of intestinal barrier, regulatory effect on gut microbiota, alteration for related metabolites, and some other possible mechanisms were summarized. And we aim to provide some references for the high-value utilization of marine polysaccharides and new targets for the treatment of gut microbiota dysbiosis by this review.

Utilization of marine macroalgae‐derived sulphated polysaccharides as dynamic nutraceutical components in the feed of aquatic animals: A review

During the last decade, indiscriminate antibiotic use has increased with intensive aquaculture practice for disease management leading to the emergence. Hence, there is a need to devise sustainable feed additives with nutraceutical value. Marine macroalgae containing natural polysaccharides have drawn attention because of their significant bioactivities. Sulphated polysaccharide is a polysaccharide containing sulphate group in sugar unit, characterized as a potential bioactive component in fish feed. These are non-digestible feed constituents and facilitate the host in multiple ways by rousing the growth and immune responses and developing a defence against harmful microorganisms and physical stressors. In aquaculture practice, marine macroalgae-derived sulphated polysaccharides are considered prebiotic substances that regulate host organisms' growth and health status. This study overviews marine macroalgae-derived sulphated polysaccharides' sources, structure, and modes of action in aquatic animals. Furthermore, the present review underscores the potential applications of marine macroalgae-derived sulphated polysaccharides in aquaculture to improve the knowledge for additional headway in this field of research. Although the effects of sulphated polysaccharides in aquatic animals have been investigated, further exploration of the mechanisms of sulphated polysaccharides on the health status of aquatic animals is required, which may open a new window during sustainable disease and growth management in the aquaculture industry.

Polysaccharides from Moroccan Green and Brown Seaweed and Their Derivatives Stimulate Natural Defenses in Olive Tree Leaves

This study aims to assess for the first time the ability of marine polysaccharides and their derivatives to stimulate natural defenses in olive tree leaves. Alginates, ALSM, and ALCM were isolated from the brown algae Sargassum muticum and Cystoseira myriophylloides, respectively. The OASM and OACM fractions were obtained after radical depolymerization of ALSM and ALCM, respectively. Three sulfated polysaccharides, arabinogalactans (AGB and AGP) and fucoidans (FUCCM) were extracted from the green alga Codium decorticatum and the brown seaweed C. myriophylloides, respectively. The extraction yield of different extracts was in the range of 0.82–32% and the average molecular weight (Mw) varied from 3000 Da to 2173 kDa. The M/G ratios of ALSM and ALCM were 0.87 and 1.12, respectively. FUCCM contained 53% of fucose and 12.83% of sulfates. The AGB and AGP fractions were characterized by the presence of a high degree of sulfation and protein (12–23% (w/w)) and were composed mainly of galactose, glucose, and arabinose. The aqueous saccharide solutions were applied to the leaf discs of the olive tree at 0.5 g/L, 1 g/L, and 2 g/L, for 24 h. These molecules triggered defense responses, by showing a differential capacity to induce the activity of the phenylalanine and tyrosine ammonia-lyase (TAL and PAL), polyphenols, and lignin contents in the leaves of the olive tree. Alginates and their derivatives as well as arabinogalactans exhibited an important induction of TAL activity compared to the PAL. The sulfated polysaccharides were more effective compared to the unsulfated polysaccharides (alginates) which were active at a low concentration. The optimum concentration for most of the studied elicitors was 2 g/L. These results suggest the valorization of these molecules derived from marine biomass as inducers of natural defenses of the olive tree to protect against phytopathogens in the context of sustainable development.